It is well known in the art that alkenylsuccinic anhydrides (ASAs) made from alpha olefins and maleic anhydride are useful as paper sizing agents in the paper industry. Paper sizing is the treatment of the cellulose fibers of paper so that the paper is resistant to liquid wetting. ASAs made from alpha olefins suffer from the drawback that they are solids which often require that they be melted or dissolved in a suitable solvent before use. It would be much easier to handle these materials if they were liquids. ASAs made from isomerized alpha olefins are generally liquids but the synthesis of ASAs from isomerized alpha olefins requires an additional olefin isomerization step.
This invention is directed to new low molecular weight branched alkenyl succinic acid derivatives (ASAD) that may be prepared by reacting a low molecular weight polyisobutene (PIB) having less than about 32 carbon atoms with an unsaturated acidic reagent. The low molecular weight branched alkenyl succinic acid derivative may be useful as is, or as an intermediate for (1) low molecular weight branched succinimides, (2) detergents or dispersants for lube oil or fuels, (3) pour point depressants, (4) surface sizing agents for paper and (5) friction modifiers for automatic transmission fluids and continuous variable transmissions (CVTs). The low molecular weight branched ASAD may be used by itself or as the ester, amide, imide or metal salt derivative of the low molecular weight branched ASAD. Preferred low molecular weight branched ASADs are liquid at ambient temperature.
It is known that olefin/unsaturated acidic reagent ASA compositions may be prepared by reacting an olefin with an unsaturated acidic reagent thermally. This reaction is typically carried out at elevated temperatures either neat or in a solvent or diluent.
One drawback to using an alpha olefin to prepare the ASA is that the resulting ASA is typically a glassy solid. A solid ASA is undesirable because a solid ASA cannot be handled easily or pumped readily at ambient temperatures. Before further processing, a solid ASA has to be brought to a consistency that may be pumped readily. Achieving such a consistency may be accomplished by heating the solid ASA to a temperature above the melting point or using a solvent to dissolve it. Heating the ASA is often costly, and the addition of a solvent is often not practical because it is desirable to remove the solvent before the ASA can be used; furthermore, the solvent has to be disposed of in a manner consistent with environmental regulations.
Additionally, in order to make a liquid product, alpha olefins can be reacted with reagents that isomerize the double bond to an internal position in the alkyl chain. When this isomerized olefin reacts with the unsaturated acidic reagent to form an ASA, the desired ASA is usually a liquid at room temperature. The addition of such an isomerization step is often costly and thus undesirable.
The low molecular weight branched ASAD of this invention is an improvement over alpha olefin ASAs. Since the low molecular weight branched ASAD of this invention is liquid, it is not necessary to dissolve the low molecular weight branched ASAD by using additional heat or adding solvent before the low molecular weight branched ASAD is used. Since no solvent is required, the step of removing the solvent is not necessary either. Also the need to isomerize the olefin to an internal olefin position, which is an additional step and can increase the cost of production of the ASAD, is not necessary for the production of the low molecular weight branched ASAD of this invention.
Boerzel et al., U.S. Pat. No. 4,152,499, disclose isobutene polymers having a degree of polymerization of from 10 to 100, where the proportion of theoretically possible terminal double bonds is greater than in conventional polybutene products.
Samson, U.S. Pat. No. 4,605,808, discloses a process for cationic polymerization of 1-olefins, particularly isobutene, thereby producing polyisobutenes with a relatively high degree of terminal unsaturation and having a molecular weight of between 500 and 5000. The high proportion of terminal unsaturation in the polyisobutene polymers are particularly suited for producing adducts with maleic anhydride.
Wurzburg et al., U.S. Pat. No. 3,102,064, disclose using substituted cyclic dicarboxylic acid anhydrides as paper sizing agents.
Onopchenko, U.S. Pat. No. 6,355,839 discloses a process for the preparation of alkylated diphenylamine antioxidant which comprises alkylating diphenylamine with polyisobutene in the presence of a clay catalyst, wherein the polyisobutylene has an average molecular weight in the range of 120 to 600 and wherein the polyisobutylene contains at least 25% methylvinylidene isomer.
DeGonia et al., U.S. Pat. No. 5,137,980, disclose the formation of polybutenyl succinic acids or acid derivatives that are useful in the manufacture of polybutenyl succinic acid esters, polybutenyl succinimides or succinamides, and polybutenyl succinic ester-amides by reaction with alcohols or amines, or combinations thereof.
Harrison et al., U.S. Pat. No. 6,156,850, disclose a process for the preparation of a polyalkyenyl derivative of an unsaturated acidic reagent. Specifically, the reaction is started in the absence of a strong acid. The strong acid is later added when at least 25% of the polyalkene is converted to a polyalkenyl derivative of an unsaturated acidic reagent.
Ratner et al., U.S. Pat. No. 3,189,544, disclose highly detergent non-ash forming mineral lubricating oil compositions. A small amount of an oil-soluble organic sulfonic acid salt of amino-imide of a long-chain monosubstituted polymeric hydrocarbyl succinic anhydride is added to lubricating oils. The long-chain polymeric substituent may be straight or branched chain and derived from olefins of from 2 to 8 carbon atoms such as ethylene, proplylene, 1-butene, isobutene, 1-hexene, styrene, alpha methyl-styrene and copolymers thereof, of from 20 to 500 carbon atoms and a molecular weight of 300 to 5000.
Ruhe, Jr., U.S. Pat. No. 5,175,225, discloses a process for preparing an oligomeric copolymer of an unsaturated acidic reactant and a high molecular weight olefin having a sufficient number of carbon atoms such that the resulting copolymer is soluble in lubricating oil and wherein at least 20 weight percent of the total olefin comprises and alkylvinylidene isomer, which process comprises reacting the high molecular weight olefin with the unsaturated acidic reactant in the presence of a free radical initiator and a solvent which comprises the reaction product of an unsaturated acidic reactant and a high molecular weigh olefin.
Zaweski, et al., U.S. Pat. No. 3,476,774, disclose a process for producing an olefinically substituted carboxylic acid or derivative by the reaction of an olefin with an alpha, beta-unsaturated carboxylic acid or derivative.
Cahill et al., U.S. Pat. No. 3,819,660 disclose suppressing fumaric acid sublimation and tar formation during reaction of 168 to 900 molecular weight alkene with maleic anhydride and increased yield of alkenylsuccinic anhydride by the use of catalytic amount of p-alkenylbenzenesulfonic acid.
Spencer et al., U.S. Pat. No. 5,777,025, disclose reacting C4-C10 dicarboxylic acid with a polyalkene at high temperature and under high inert gas partial pressure in the presence of a sediment-inhibiting amount of hydrocarbyl substituted sulfonic acid.
Davison, R. W., “The Sizing of Paper,” TAPPI, Vol. 58, No. 3 (March 1975) pp. 48-57, summarizes qualities of paper sizing agents.